Low performance of the IDE on the SIS550
Yves.Godin at lyrtech.com
Thu Oct 3 07:52:01 CEST 2002
I have a board based on the SIS550 (Vortex86 @167 MHz) and I wantd to
setup a NFS file server that is capable to sustain 10 MBytes/s. But the
problem is that the IDE interface seems very slow in writing. I patch my
kernel (2.4.19) with the patch for the 5513 and now the controller is
recognise as a ATA-100a but when I try to put the controller un UDMA mode
mode 5, I got a message from hdparm that told that it is not supported.
Anyway, with the UDMA mode 2 I should have the performance that I need. I
look on header of the ide connector and the burst when writing seems to be
quick anough but between each of these bursts I have a hole of 5-6 seconds.
I test the speed with theses commands:
time dd if=/dev/zero of=zero bs=1k count=100k -> WRITING
-> 30 sec
time dd if=zero of=/dev/null bs=1k count=100k -> READING
-> 10 sec
I try all configuration possible (hdparm) for the harddisk and 3 MB/s is
the best result that I got. In PIO mode 4, I only got a 1.5 MB/s !
I performed theses tests on different architecture and I got the following
SC520 PIO (ISA) -> 1.63 MB/s
SC1210 PIO -> 4.54 MB/s -> I was unable to enable the DMA ????
P133 ATA-33 -> 5.50 MB/s
PII-266 ATA-33 -> 17.83 MB/s
PII-400 ATA-33 -> 20.54 MB/s
C3-667 ATA-100 -> 23.05 MB/s
Does anyone have an idea why:
1. I cannot enable the UDMA mode 5 ?
2. I only got 3 MBytes/s in writing ?
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